Two-dimensional vanadium-doped ZnO nanosheet-based flexible direct current nanogenerator
Manoj Kumar Gupta1, Ju-Hyuck Lee, Keun Young Lee
1School of Advanced Materials Science and Engineering, ‡SKKU Advanced Institute of Nanotechnology (SAINT), Center for Human Interface Nanotechnology (HINT), and §IBS Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Sungkyunkwan University (SKKU) , Suwon 440-746, Republic of Korea.
ACS Nano
|September 6, 2013
Summary
Researchers developed lead-free vanadium-doped zinc oxide nanosheets for flexible piezoelectric nanogenerators. These novel materials surprisingly produced direct current (DC) output, unlike traditional alternating current (AC) generators.
Area of Science:
- Materials Science
- Nanotechnology
- Solid State Physics
Background:
- Zinc oxide (ZnO) nanostructures are widely explored for piezoelectric applications.
- Traditional ZnO nanogenerators typically produce alternating current (AC) output.
- Developing lead-free, high-performance piezoelectric materials for flexible electronics remains a challenge.
Purpose of the Study:
- To synthesize lead-free, single-crystalline, two-dimensional (2D) vanadium(V)-doped ZnO nanosheets (NSs).
- To investigate their application in high-performance flexible direct current (DC) power piezoelectric nanogenerators (NGs).
- To understand the mechanism behind the observed DC output and enhanced piezoelectric performance.
Main Methods:
- Synthesis of vanadium(V)-doped ZnO nanosheets (NSs) from vertically aligned ZnO nanorods (NRs).
- Characterization using piezoresponse force microscopy (PFM) to study ferroelectricity and piezoelectric properties.
- Fabrication and testing of piezoelectric nanogenerators (NGs) under compressive force.
Main Results:
- Vanadium doping transformed ZnO nanorods into 2D nanosheet networks.
- V-doped ZnO NSs exhibited ferroelectricity with clear phase, butterfly, and hysteresis loops.
- Piezoelectric charge coefficient reached up to 4 pm/V in 2D nanostructures.
- V-doped ZnO NS-based NGs generated a DC output current density up to 1.0 μAcm(-2), a significant departure from AC output of pristine ZnO NR-based NGs.
Conclusions:
- Vanadium doping induces ferroelectricity and a charge inversion phenomenon in ZnO NSs.
- The formation of an ionic layer ([V(OH)4(-)]) and doping-induced resistive behavior contribute to the DC output.
- These lead-free V-doped ZnO NSs offer a promising pathway for high-performance flexible DC piezoelectric nanogenerators.
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